For this scene I created a material in Unreal Engine 4 which enables me to use vertex painting to transition between three different textures. I used this to create realistic wear and rust on the walls and pipes that is applied in a non-repetitive way over multiple modular pieces.
This video demonstrates the vertex painting in action.
This material uses the red channel of the vertex painting to act as a mask for three different tillable textures. It splits up the gradient between black and red into three sections and assigns each to a different texture. In order to create a natural transition between the three textures, a noise texture is applied to the mask as well. This process shown for the base color is repeated for the roughness and normal textures so that it is consistent across the PBR material.
